The invention relates to a drive device for a hinged side window of a vehicle.
A drive device is known from DE 197 06 951.7. This drive device has proved successful in practice, since, on the one hand, the necessary transmission of force from the actuating drive to the hinged side window via the operating lever can be carried out in a very small space, because all the elements have a compact design and force is transmitted along the longitudinal axis of the rotary shaft by means of the rotation of the latter. Other advantages are to be seen in that the reduction gear is arranged in the region of the operating lever, so that said gear takes up only a small amount of construction space, whilst the actuating drive can be mounted at a location in the vehicle, in particular under the rear shelf unit, at which only a small amount of construction space is usually available. Furthermore, the operating lever, designed as a toggle lever, has the advantage that, in the closed position, the hinged side window cannot be opened by force, since the dead center of the toggle lever cannot be overcome from outside.
Despite all the advantages, however, there is still the disadvantage that the drive device as a whole works noisily, since particularly the reduction gear gives rise, when the hinged side window is being opened or closed, to unpleasant noises which have a disturbing effect on the vehicle occupants.
The object on which the invention is based is, therefore, white preserving the advantages described, to improve the drive device in such a way that the noise emission of the drive device is effectively reduced and low-noise movement of the hinged side window from one position into the other, along with the least possible wear, is ensured.
The advantage of providing the reduction gear as a worm gear is that it is possible, in a very small space, to achieve a reduction which optimally utilizes the available construction space by virtue of the geometric design of the worm gear (gearwheel on the operating lever and worm wheel at the end of the transmission element). It must be remembered, here, that very little construction space is available in the region in which the operating lever (toggle lever) is arranged, because, on the one hand, the operating lever should not project too far into the interior, so as to avoid risks of injury, and, furthermore, it should have an agreeable appearance. Moreover, the force necessary for moving the hinged side window has to be transmitted in the small construction space. All this is ensured by designing the reduction gear as a worm gear. It is also advantageous that the worm gear has involute toothing, thus ensuring that the drive device as a whole runs quietly. This involute toothing also has the advantage that simple and accurate production by the enveloping cut method (particularly in the case of a straight-flanked reference profile of the worm gear) is possible and, furthermore, the worm gear has interchangeable wheel properties, by means of which uniform movement transmissions, even in the case of center-to-center deviations, are possible. This is particularly important in the large series production of the drive device according to the invention, since the production costs fall in a beneficial way if there is an optimum cycle of movement and, at the same time, the precision required is not too high.
In a development of the invention, the involute toothing has a protuberant profile. The advantage of such a protuberant profile is that the tooth root of the gearwheels, in particular of the gearwheel meshing with the worm, cuts freely, so that notches caused by the rubbing of the toothing are avoided. If a large tooth depth, in particular more than double the useful flank, is selected, particularly quiet-running properties are possible. The gearwheels can be produced in large quantities in a simple way by appropriately shaped protuberant tools, and, here again, the costs of large series production are lowered.
In a development of the invention, the worm gear is made to be self-locking thus ensuring the hinged side window is detained in any desired position between its closed position and its open position after the actuating drive of the drive device has been switched off in this position just set, so that fluttering of the hinged side window is avoided. Moreover, in the closed position, the risk of break-ins is reduced.
In a development of the invention, one gearwheel of the worm gear consists of metal, whilst the other gear wheel consists of plastic. This choice of material also, again, ensures particularly quiet running properties of the drive device, and, here, not only is the use of metal and plastic considered for the worm gear in the region of the operating lever, but such pairings of material may also be employed in a gear which, if appropriate, is used in the actuating drive. The pairing of metal/plastic material also has the advantage that there is no need for interference suppression measures which would be necessary in the case of a pairing of metal/metal materials.
In a development of the invention, the worm wheel consists of brass and the gearwheel of the plastic polyoxymethylene, with the result that the worm wheel can be very easily connected, in particular soldered or welded, to the rotary shaft of the transmission element. This eliminates a fault source, specifically if different pairings of material have to be connected to one another. This would be the case if the rotary shaft were to consist of a metal and the worm wheel a plastic. Should different pairings of material nevertheless be used for the rotary shaft and the worm wheel or for the gearwheel meshing with the worm wheel and the operating lever, connections by positive locking are particularly advantageous, since such positive locking is virtually independent of the pairing of material. The choice of material is particularly advantageous because the running properties are very good, a particularly long service life, in particular over a life cycle of the vehicle, is afforded and interference signals, which would occur in the case of a pairing of metal/metal material are also avoided.
In a development of the invention, the operating lever has at least two levers, the two levers being rotatably connected to one another, and one lever being arranged on the hinged side window and the other lever being arranged rotatably on the part fixed to the body. In order to operate the operating lever (the toggle lever), one lever is connected to the gearwheel, and this, in turn, may be carried out, for example, by positive locking. A particularly advantageous design is afforded when the lever and the gearwheel form a structural unit, the lever and the gearwheel being produced, in particular, from the same material (plastic) and the connection being achieved by adhesive bonding. Furthermore, it is also conceivable for the lever and the gearwheel to form a structural unit in the sense that both parts are shaped in one production step.
In a development of the invention, a mounting is provided only in the region of the worm wheel and the end of a rotary shaft in the transmission element. If the mounting in this region is given appropriate dimensions, further mountings, in particular a bearing point at the end of the worm wheel arranged on the rotary shaft, may be dispensed with, so that, again, the scant construction space is optimally utilized.